Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.3.13 (lysyl oxidase)
 1,248 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The substrate specificity of lysyl oxidase has been explored with synthetic oligopeptides. kcat/Km increased with increasing peptide length in Ac-(Gly)n-Lys-(Gly)n-CONH2 (n = 1-5). Using 11-mers as the standard peptide length, Glu immediately N-terminal to Lys increased kcat/Km 8.8-fold over that for the -Lys-Glu- sequence and 4.9-fold over the glutamate-free control. Kinetic constants were significantly less perturbed when Glu was 2 or more residues distant from Lys. Replacement of Glu in -Glu-Lys- with Gln significantly increased Km and lowered kcat/Km. Asp rather than Glu N-terminal to Lys decreased Km similar to that of the -Glu-Lys- 11-mer, although the kcat decreased considerably, indicating that lysyl oxidase responds to the side chain length of vicinal Asp or Glu at this position. -Asp-Glu-Lys- within an 11-mer was not oxidized, although this sequence is oxidized within the N-terminal telopeptide of the alpha 1(I) chain in type I collagen fibrils. Thus, lysyl oxidase exhibits distinct preferences for sequences vicinal to lysine. These results are discussed with respect to a model requiring collagen fibril formation prior to oxidation of lysine in collagen by lysyl oxidase.
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PMID:Modulation of lysyl oxidase activity toward peptidyl lysine by vicinal dicarboxylic amino acid residues. Implications for collagen cross-linking. 791 81

Key aspects of the biosynthesis and catalytic specificity of lysyl oxidase (LO) have been explored. Oxidation of peptidyl lysine in synthetic oligopeptides is markedly sensitive to the presence of vicinal dicarboxylic ami/no acid residues. Optimal activity is obtained with the -Glu-Lys- sequence within a polyglycine 11-mer, whereas the -Lys-Glu- sequence is much less efficiently oxidized. The -Asp-Glu-Lys- sequence is a very poor substrate, although this sequence is oxidized in type I collagen fibrils. These results are considered in the light of a model requiring collagen to be assembled as fibrils prior to oxidation by LO. An in vitro system for the expression of catalytically active LO has been devised. Deletion or inclusion of the cDNA coding for the propeptide region in the expressed construct results in apparently identical, catalytically active enzyme products, indicating the lack of essentiality of this region for active enzyme production. These effects are considered with respect to the conservation of the amino acid sequence of LO produced by different species.
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PMID:Catalytic properties and structural components of lysyl oxidase. 857 53